Using Sustainable Drainage Systems

Using SuDS

You can use sustainable drainage systems (SuDS) to treat lightly polluted water that runs off from your site, reducing the impact on the environment.

You must not use SuDS to treat sewage, heavily contaminated run-off or trade effluent. If you cause or allow surface water or groundwater pollution you may be committing an offence and may be prosecuted and fined or imprisoned.

What you must do

In Northern Ireland

You may have to include plans for SuDS when you apply for planning permission for new developments. It is good practice to include the use of SuDS in all development plans.

In Scotland

You must consult with the Scottish Environment Protection Agency (SEPA) before discharging any run-off from your site to surface waters or groundwater. If you discharge to a sewer you will need a consent or agreement from your sewerage provider. If you discharge any run-off without an authorisation you may be prosecuted.

All new developments must use SuDS to control surface water run-off to the water environment, unless the run-off is from a single dwelling or is to coastal waters.

GBR 10 details the rules relating to discharging water from a surface water drainage system. 

GBR 10 covers all surface water discharges, including those requiring SuDS, from:

  • land used for residential purposes (up to 60 hectares).
  • land used for non-residential premises or yards (excluding industrial estates).
  • car parks with up to 1,000 spaces.
  • metalled roads (excluding motorways and A roads).
  • waterbound roads.

and

  • constructions sites, where the site, including any constructed access tracks does not:
    • exceed 4 hectares.
    • contain a road or track longer than 5km.
    • include any area more than 1 hectare, or any length of more than 500m on ground with a slope of more than 25°. 

If your site exceeds these thresholds then you will require authorisation from: SEPA: Construction Regulatory Guide

For further information see - The Water Environment (Miscellaneous) (Scotland) Regulations 2017, schedule 3, Activities 10 and 11 - Discharges of water run-off  (GBR 10 and 11)

SuDS must be:

  • designed to prevent pollution of the water environment
  • designed to protect the bed and banks of the receiving surface water
  • maintained in good order
  • protected from materials that will damage or block the system.

If your site was constructed after 1 April 2007, you must not discharge untreated surface water which contains run-off from:

  • fuel delivery or refuelling areas
  • areas where potentially polluting materials - such as chemicals and oil - are delivered, handled or stored.

If you discharge surface water run-off from a construction site, you must use suitable SUDS techniques.

Good practice (NI and Scotland)

Run-off from hard paving is likely to be contaminated by oil, organic material or toxic metals. Where there is a high risk of contamination by oil, you may need to install an appropriate oil separator in the drainage system.

GPP 3 Use and design of oil separators in surface water drainage systems

Where possible, you should design SuDS to increase biodiversity and provide habitats for wildlife in the area they drain.

For further information on measures to control water pollution, see our guideline: Preventing water pollution.

Further information

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